Medical imaging systems allow medical professionals to view a subject's internal features with minimal risk to the subject in terms of radiation exposure. Medical imaging systems image subjects by utilizing a variety of technologies such as Fluoroscopy, Computerized Tomography (“CT”), Magnetic Resonance Imaging (MRI), and Ultrasound. In CT scanning, a slice or tomographic slice is created by rotating an x-ray source and an image receptor partially or completely around a subject. Tomography utilizes a fulcrum reference, which is determined by adjusting the patient distance from the center of the perpendicularity of the x-ray source and x-ray receptor. The slice depth is determined by the distance of the subject from the center of the perpendicularity. A three-dimensional image of these slices can be constructed by compiling the images together as layers. Magnetic resonance imaging utilizes similar technology as a CT scanner except that a MRI device utilizes a magnetic field and radio signals to accomplish the tomographic planar image. The three-dimensional MRI images can be constructed from the MRI slice images. Ultrasound utilizes sound echoing technology to create a two-dimensional ultrasound image relative to a single plane in reference to the position of the ultrasound device and the angle the device is placed in reference to the subject being imaged. A three-dimensional ultrasound image can be reconstructed from the combination of the different two-dimensional ultrasound images.
Fluoroscopy systems utilize an image source, e.g., x-ray source, and an image receptor, to provide a real-time display of a two-dimensional fluoroscopic image in reference to a single plane, either AP (anterior/posterior) or any angle where the subject is perpendicular to the plane of the image source and image receptor. The image source and image receptor may be rotated partially around the patient, thus placing the image source and image receptor at different angles perpendicular to the patient, in order to create a plurality of two-dimensional fluoroscopic images.
For procedures such as angioplasty, where a device is placed inside an artery or vein and moves throughout the artery or vein, or pain management, where a needle is introduced into a specific area of the spine and it is desirable to view the exact area where the needle is introduced, a three-dimensional real-time or a three-dimensional continuously updatable imaging system may be desirable. In current systems utilizing MRI, CT, Ultrasound, or Fluoroscopy, three-dimensional (3D) images may be reconstructed from a plurality of two-dimensional images, however the reconstruction is normally done in post-processing, and not in real-time. In other words, it may take a few hours to completely scan or 360 scan the patient using other imaging technologies and even more time to construct or reconstruct a 3D image from the plurality of two-dimensional images. The 3D images are normally reference images that are later used for analysis by medical personnel. If the 3D image needs to be updated, e.g., to track the path of the angioplasty device through the artery or vein, a complete new 3D image would need to be created, meaning the entire area of the subject would need to be rescanned, which as mentioned before, can be a time-consuming process. Thus, it is desirable to be able to view only a specific subset of the scanned area or the complete 360 scanned area while the procedure is occurring, and to have this specific subset of the scanned area or the 360 scanned area be updated continuously or in real-time.